A concise overview of mammalian spermatogenesis

The male gamete, the spermatozoon, is the carrier of paternal inheritance. Besides paternal genome, the spermatozoon contributes essential factors for successful fertilization, embryonic development, and continuation of species. A dynamic and extraordinarily complex process called spermatogenesis produces spermatozoa capable of maturing and acquiring full fertilizing capacity. Spermatogenesis proceeds through a series of events that involve cell division (proliferative phase assuring continuous restocking of spermatogenic stem cells), meiosis (recombination and haploidization of paternal genome), post-meiotic differentiation (spermiogenesis; hypercondensation of sperm DNA and generation of accessory sperm structures), and post-testicular maturation (including epididymal maturation, acquisition of seminal plasma components at ejaculation and spermatozoa capacitation within the female oviduct). In this chapter, we provide a concise overview of testis organization and spermatogenesis in different mammalian species and the details of the intricate structure of human/mammalian spermatozoa. Additionally, we explore the fascinating process of spermatogenesis and its regulation. We thus aim to offer insights into the fundamental process that drives male fertility and provides the foundation of reproductive success.